Piston



March 1, 1960 G. A. FLAMM' 2,926,644

PISTON Filed July 26, 1957 2 Sheets-Sheet 1 TIE- l 6 J3 INVENTOR:

Gerald A .flamm,

March 1, 1960 Filed July 26, 1957 I G. A. FLAMM PISTON 2 Sheets-Sheet 2 INVENTOR;

GeraZdA-f'lamm,

2,926,644 PlSTON Gerald A. Flamm, Reading, Pa.

Application July 26, 1957, Serial No. 674,376

6 Claims. (Cl. 123-65) "Ihis'invention relates to pistons for compression-ignition and other type-internal combustion engines, and more particularly concerns a piston which is designed, or adapted for use, in the cylinder of a-two stroke cycle internal combustion engine, which cylinderhas two opposed fuel gas intake, or by-pass passages.

In general, pistons for internal combustion engines have heretofore been variously constructed for the purpose of improving their operating effectiveness and efficiency. For example, in such pistons the crown surface thereof has been provided with a vertically extending fuel gas directing baffie (US. Patent 2,136,416), or with recesses for the valve heads (U.S. Patent 2,420,474), or with spiral troughs, or scoops (US. Patent 2,709,992), or with an arcuate-shaped groove that curves around the 'center of the piston crown surface (US. Patent 1,841,796), etc. However, these and other similar piston crown developments have not satisfactorily, or suc cessfully, solved the problem of effecting maximum piston crown construction simplicity coupled with maximum piston power output, particularly in pistons adapted for use in internal combustion engines of the miniature type that are utilized for operating airplane models and the like, or in which the piston reciprocates in a cylinder having two opposed fuel gas intake, or by-pass passages, and two opposed exhaust gas passages.

One object of my invention is to provide a novel piston which solves the indicated problem.

Another object is to provide such a piston which has certain structural and functional features of advantage over the similar prior art pistons.

A further object is to provide such a piston having a flat or other shaped circular crown surface provided with a straight diametrically extending groove of substantially rectangularly-shaped configuration, which groove functions to determinedly direct and scoop up the fuel gas entering the cylinder in such manner as to attain a more effective, and efficient distribution, mixture, or turbulation of said gas in the cylinder prior to .its explosion, than heretofore possible, and a resultant increase in the power delivered by the piston.

An additional object is to provide such a piston in which the said fuelgas directing groove in the piston crown surface is arranged in straight crosswise aligned relation with said cylinder fuel gas'intake passages ofa two stroke-cycle internal combustion engine, and which groove may be provided in the form of one of a variety of different configurations that are all substantially equally equally effective in carrying out the function and purpose previously indicated.

Pistons for internal combustion engines of the type indicated are normally pivotally connected with one end of a link, or connecting rod, by a crosswise extending pin that is anchored in the wall of the piston head, the other end of which rod is joined with the crankshaft of the engine. Such prior art pivotal connecting arrangements between the piston head and the connecting rod,

particularly in the miniature type internal combustion "ice engines referred to, require a certain amount of skill, care and time, to effect the proper assemblage thereof during the engine manufacturing process.

Another object of my invention is to provide a piston head structure having a novel and simple separable connecting arrangement for pivotally joining the said connecting rod with the piston head in such manner as to facilitate the assembly procedure thereof during the engine manufacturing process and thereby substantially eliminatethe said skill, care and time heretofore required.

Another feature of my invention resides in a novel, simple and rugged piston structure that embodies both means adapted to attain maximum operating efficiency thereof, as well as means adapted to facilitate, in time saving manner, its connection with the crankshaft of the internal combustion engine with which it is associated.

With these and other objects in view, which will" be' come more apparent from the following detailed descrip tion of several practical and illustrative embodiments of my improvements shown in the accompanying drawings, my invention comprises the novel piston structure, elements, features of construction and arrangement of parts in cooperative relationship, asinore particularly indicated and defined by the hereto appended claims.

In the drawings:

Figure l is a top plan view of a novel piston for internal combustion engines, which piston embodies my invention.

Fig. 2 is a side elevationalyiew of the piston shown in Fig. 1.

Fig. 3, is a side elevational view of the piston shown in Fig. l, but with the crown portion thereof partly broken away along a line as indicated by the arrows 3-3 on Fig. 1.

Figs. 4 and 5 are views similar to Fig. 3, but of modified piston crown portions in accordance with my invention.

Fig. 6 is a top plan view of my improved piston in association with a cylinder of a two stroke-cycle internal combustion engine of the type having two opposed fuel gas intake, or by-pass passages, and two opposed exhaust gas passages.

Fig. 7 is a central, elevational, cross-sectional view, taken substantially as indicated by the arrows 7-7 on Fig. 6, but with a top portion of the engine cylinder block, or head, added.

Fig. 8 is a sectional view, similar to Fig. 7, but taken as indicated by the arrows 8-8 on Fig. 6.

Fig. 9 is a cross-sectional view of the piston cylinder only, taken as indicated by the arrows 9-9 on Fig. 7, and

Fig. 10 is a plan view of a spring element which forms part of my invention.

Referring to the drawings, in which similar reference characters designate corresponding parts, one form of my piston invention is shown by itself in Figs. 1 and 2. Figs. 6, 7 and 8 show my improved piston in working association with certain well known parts of a two strokecycle internal combustion engine of the miniature type used for operating airplane models and the like. While I have shown my improved piston in association with such a two stroke-cycle engine, it is to be understood that my piston invention is not to be construed as limited in its application and use to such engines and that it can be utilized with other types of internal combustion engines where the inventive features of the piston structure can provide substantially the same, or similar, structural and functional advantages and beneficial results.

The piston shown in said figures generally comprises, a

cylindrical preferably light weight metallic piston head 1, having a flat circular piston crown surface 2, a plu rality of piston ringside grooves 3, a straight diametricaliy arranged substantially rectangularly-shaped fuel gas directing groove 4, and a separable connecting device for a usual connecting rod R, which device is mounted within the cylinder head l and includes a cylindrical element 5, an expandable ring-shaped spring element 6 and two small metallic pins 7 and 8 that are secured in the upper end of the element and are adapted to be slidingly projcoted into slightly larger socket-like anchoring or receiving apertures 9 and 19 formed in the cylinder head 2.

The upper end of the usual type piston connecting rod R is pivotally mounted within the cyindrical element 5 by a crosswise extending pin 11,'the ends ofwhich are seated in side wall apertures 12 and 13 of the element 5, and the lower end of said connecting rod R is pivotally secured in usual manner to the engine crank shaft, not show i i Asi ndicated in Figs. 7 and t3, usual type piston rings 15!, may be mounted in the piston ring grooves 3, whet} ever the cylinder arrangement in which'the piston opera ates, is suitable for piston ring cooperation, in well known manner. However, thepiston of my invention may also be provided with a piston head that is devoid of such a piston ring arrangement and instead the upper end side edge surface portion of the piston head may be reduced somewhat in diameter, or an annular groove formed in the outer piston wall surface at this location to prevent binding of the piston due to'heat expansion of the metal during operation of the piston. a

In Figs 6, 7, 8 and 9 are indicated certain well known combustion engine parts with which the piston of my invention is adapted to be cooperatively associated; The said. indicated parts generally comprise a metallic piston cylinder 15 having two similar opposed fuel gas intake, or by-pass passages 16 and 17, and two similar opposed exhaust gas outlet passages, or ports 18 and 19. The usual type engine head is'partly indicated at 20 and a threaded aperture is shown at 21 in which a standard or conventional glow type, or other spark plug (not shown) is mounted for the purpose of properly igniting the fuel gas that is compressed by the piston in the cylinder portion above the fuel intake passage and exhaust gas outlet port arrangement, in timed relation with the two stroke-cycle principle of operation of a combustion engine having the parts indicated.

In accordance with the well known principle of operation of a two stroke-cycle internal combustion engine of the" type with which my piston'invention has been shown associated to illustrate a practical and exemplary use thereof, the two stroke-cycle is substantially as follows:

The fuel gas from the gas supply flows from the upper end of the two opposed fuel intake, or by-pass passages 16 and 17, directly into the upper portion of the cylinder 15 and during the upward movement, or stroke, of the piston head 1, the fuel gas is directed and scooped up by the groove 4 and is then compressed in the upper cylinder portion above the fuel intake passages and exhaust gas ports. A spark from the spark plug then ignites the compressed fuel gas and the explosion of the gas causes the piston to move downwardly so as to carry out its downward stroke. As the piston crown surface passes downwardly along the exhaust ports 18 and 19 the burnt gas escapes therethrough, and this escape action of the burnt gas is assisted by the simultaneous entry of fresh fuel gas through the by-pass passages 16 and 17. After a short period of operation of the engine, sufiicient heat is developed in the upper partof the cylinder wall and the therewith associatedparts, to effect the spontaneous explosion of the compressed fuel gas in properly timed relation with the engine cycle, without the aid of a spark fromthe spark plug and the sparking operation of the latter may consequently be discontinued. The spark plug used may be of the type that glows when sufficiently heated so, that the glowing action of the plug will function to effect or assistthe ignition of the fuel gas without,

sparking action after said short heating-up period of operation of the engine. v

I have found in practice that the power developed by the downstroke of the piston can be increased in the order of about ten percent by providing the piston crown surface 2 with a groove 4 as shown. The width of the rectangularly-shaped groovev 4, as more particularly shown in Figs. 1 and 3, is substantially one-half of the diameter of the piston, and the ends of the groove 4 terminate at points that are spaced a distance of about 5 percent of the piston diameter from the edge'of the piston crown surface. The bottom surface of the groove 4 is of arcuate shape, the radius of which is in the order of .7 to 5 times the diameter of the piston. The side walls of the groove 4 are in perpendicular relation with the flat circular piston crown surface. I

By providing the arcuate groove '4 in the piston crown Surface ho n. the fuel as it as from th upp en of th fue as pass es .16 Will be deter m n d rec ed o used 'toflow' 'y use tows-e the central area of theupper portion of the cylinder 15, instead of being permitted to iiow a haphazard manner, as heretofore, with the prior art piston crown surface arrangements. The cavity formed in the piston crown surface by the groove 4 will also effect scooping accumu-' lation of more fuel gas for compression. Furthermore, the groove 4, in performing its fuel gas directing function, increases the mixing or turbulating action of thefuel gas, and effects a more uniform distribution thereof, before it is compressed and ignited, thereby effecting better fuel conditioning and a resultant more efficient operation of the engine with which my improved piston is associated.

Substantially the same beneficial and advantageous results can be accomplished by providing a piston structure having a groove in the piston crown surface thereof, .as illustrated "by the modified forms of my invention shown in Figs. 4 and 5, the width of each of which grooves is substantially the same as the width of the groove 4 already described. Since the piston structures of Figs. 4 and 5 are otherwise, the same as the piston structure pre viously described, those parts of the piston structure of Figs. 4 and 5 which are similar to the already described piston parts have applied thereto the same reference characters withthe exponent a? and b respectively added thereto for purposes of differentiation.

The modified groove 22 of Figure 4 has two straight bottom segment surfaces 223 and 22* that diverge upwardly relatively to each other from the piston axis, or center, to termination points directly adjacent'to and spaced from the edg e' offtheipiston crown surfaces as previously indicated. The angle of inclination of-eachof t bottom sur aces ameut andZlZ. he oo 2 i e o d r Qt to 25 de re s. th th h i ont piston crown surface.

Fig.5 sh s a m d fie sroovegfi h vinsabo tom surface 23 and similar opposed end surfaces. 213 and 23 that are inclined relative to, the flat piston crown surface 2 at an angle of about 45. degrees. The bottom surface 23 of the groove 23 is in parallelism with the piston crown surface 2. The outer or termination ends of the inclined surfaces 23* and 23 are spaced from the edge of the piston crown surface 2 a distance which in length is equal to about 5 percent of thelength of the piston head diameter. 7 I v I The improved means, or device, for connecting the piston rod R to the piston head 1, willbe morereatlily understood by referring to Figs. 7, 8 and 10 and the following further description thereof:

e P t h ad 1 is o n. t ts b tom. endand i 12 10- vided with an internal cylindrical wall surfacp ehZfi of the same diameter throughout, in which isforrned an annular spring ring receiving groove 25 at the location shown.

The cylindrical metallic element 5 is of slightly lesser outside diameter than the internal piston head surface 2 o a he e em n ,5 can heslid ns y i serted into the bottom end of the piston head 2 and moved to it: properly seated location shown in Figs. 7 and 8.

After the upper end of the piston rod R has been connected with the element 5, by the pin 11 inserted through, and having its ends seated in, the wall apertures 12 and 13, the element 5 is inserted in the bottom end of the piston head 1 and moved upwardly until the pins 7 and 8 are seated in the socket-like apertures 9 and 10 and the top surface of the element 5 is in contacting relation with the internal flat circular surface at the upper end of the cylindrical surface 24. The spring ring 6, which may be formed of spring brass, or the like, is then expandingly seated in the groove 25 as shown, thereby, locking the element 5 against removal from the piston head 1.

The pins 7 and 8, that are secured in the upper end of the element 5, function to prevent lateral movement of the element 5 relative to the piston head 1.

Since the weight of the element 5 is added to the weight of the piston head 1 in its reciprocating movement in the cylinder 15, it is desirable that the weight of the element 5 be kept at a minimum and for this purpose the metallic mass thereof can be reduced in any practical manner, for example, by the elimination of metal at the top end thereof as effected by the provision of a circular aperture 26.

Of course, the novel piston developments specifically shown and described, can be changed and modified in various ways without departing from the invention herein disclosed and more particularly defined by the hereto appended claims.

I claim:

1. A piston for use in the cylinder of a two strokecycle internal combustion engine which cylinder has two opposed fuel gas by-pass passages and two Opposed exhaust gas passages; comprising a piston crown surface provided with a diametrically arranged elongated concave arcuate groove of substantially the same width as said passages arranged in crosswise aligned relation with said cylinder fuel gas by-pass passages between points directly adjacent to the edge of said piston crown surface.

2. A piston for use in the cylinder of a two strokecycle internal combustion engine which cylinder has two opposed fuel gas by-pass passages and two opposed exhaust gas passages; comprising a flat circular piston crown surface provided with a diametrically arranged rectangularly-shaped elongated groove of substantially the same width as said passages arranged in crosswise aligned relation with said cylinder fuel gas by-pass passages, the bottom surface of which groove is in parallelism with said flat piston crown surface and the outer ends of which groove diverge angularly upwardly to a termination point directly adjacent to the edge of said piston crown surface.

3. A piston for use in the cylinder of a two strokecycle internal combustion engine which cylinder has two opposed fuel gas by-pass passages and two opposed exhaust gas passages; comprising a piston crown surface provided with a diametrically arranged elongated groove of substantially the same width as said passages arranged in crosswise aligned relation with said cylinder fuel gas by-pass passages, the bottom of which groove is defined by two straight flat surfaces that converge toward each other from diametrically opposed points directly adjacent to the edge of the piston crown surface to the center point of the piston.

4. A piston for use in the cylinder of a two strokecycle internal combustion engine which cylinder has two opposed fuel gas by-pass passages and two opposed exhaust gas passages; comprising a piston crown surface provided with a diametrically extending elongated groove that is arranged in crosswise aligned relation with said cylinder fuel gas by-pass passages between points short of the piston crown edges, the said groove having a bottom surface of arcuate concave configuration and substantially flat side walls that reach their maximum height in the central portion of said piston crown surface.

5. A piston for use in the cylinder of a two strokecycle internal combustion engine which cylinder has two opposed fuel gas by-pass passages and two opposed ex haust gas passages; comprising a circular piston crown surface provided with a diametrically extending rectangu- 'larly-shaped elongated groove that is arranged in crosswise aligned relation with said cylinder fuel gas by-pass passages between points short of the piston crown edges, the said groove having a bottom surface arranged in parallelism with said flat piston crown surface and outer end areas diverging angularly upwardly to said points short of the edges of said piston crown surface and having substantially fiat side walls.

6. A piston for use in the cylinder of a two strokecycle internal combustion engine which cylinder has two opposed fuel gas by-pass passages and two opposed exhaust gas passages; comprising a circular piston crown surface provided with a substantially V-shaped groove that is arranged in crosswise aligned relation with said cylinder fuel gas by-pass passages between points short of the piston crown edges, the said groove having substantially flat side walls that reach their maximum height in the central portion of said piston crown surface.

References Cited in the file of this patent UNITED STATES PATENTS 1,607,398 Hildebrand Nov. 16, 1926 1,789,089 Tobler Jan. 13, 1931 2,119,121 Steinlein May 31, 1938 2,122,677 Bourke July 5, 1938 2,445,715 Jennings July 20, 1948 2,447,508 Kleinfeld Aug. 24, 1948 2,516,031 Taluio July 18, 1950 2,815,993 Schweitzer Dec. 10, 1957 2,819,936 Cambeis Jan. 14, 1958 2,823,085 Keylwert Feb. 11, 1958 2,838,035 Rice June 10, 1958 FOREIGN PATENTS 664,461 Germany Aug. 27, 1938 671,028 Germany Jan. 30, 1939 680,906 Germany Sept. 9, 1939 894,635 Germany July 8, 1949 423,829 Italy Dec. 12, 1946 674,534 Great Britain Mar. 15, 1950 155,062 Sweden June 27, 1951 

